Pietro Baldelli

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The synapsins are a family of neuronal phosphoproteins evolutionarily conserved in invertebrate and vertebrate organisms. Their best-characterised function is to modulate neurotransmitter release at the pre-synaptic terminal, by reversibly tethering synaptic vesicles (SVs) to the actin cytoskeleton. However, many recent data have suggested novel functions(More)
In voltage-dependent ion channels, the gating of the channels is determined by the movement of the voltage sensor. This movement reflects the rearrangement of the protein in response to a voltage stimulus, and it can be thought of as a net displacement of elementary charges (e0) through the membrane (z: effective number of elementary charges). In this(More)
Using the cell-attached recording configuration, we found that in adult bovine chromaffin cells there exists a direct membrane-delimited inhibition of single Bay K-modified L-channels mediated by opioids and ATP locally released in the recording pipette. This autocrine modulation is mediated by pertussis toxin (PTX)-sensitive G-proteins and causes a 50 %(More)
T-type channels are expressed weakly or not at all in adult rat chromaffin cells (RCCs) and there is contrasting evidence as to whether they play a functional role in catecholamine secretion. Here we show that 3-5 days after application of pCPT-cAMP, most RCCs grown in serum-free medium expressed a high density of low-voltage-activated T-type channels(More)
Voltage-gated L-type (Cav1.2 and Cav1.3) channels are widely expressed in cardiovascular tissues and represent the critical drug-target for the treatment of several cardiovascular diseases. The two isoforms are also abundantly expressed in neuronal and neuroendocrine tissues. In the brain, Cav1.2 and Cav1.3 channels control synaptic plasticity, somatic(More)
We have studied the functional role of CaV3 channels in triggering fast exocytosis in rat chromaffin cells (RCCs). CaV3 T-type channels were selectively recruited by chronic exposures to cAMP (3 days) via an exchange protein directly activated by cAMP (Epac)-mediated pathway. Here we show that cAMP-treated cells had increased secretory responses, which(More)
Ca2+ channels diversity of cultured rat embryo motoneurons was investigated with whole-cell current recordings. In 5-20 mM Ba2+, the whole-cell currents were separated in low- (LVA) and high-voltage-activated (HVA) current. The LVA current was evident since the first day in culture, while the HVA component was small and increased with time. Recordings after(More)
Protein kinase A (PKA) modulates several steps of synaptic transmission. However, the identification of the mediators of these effects is as yet incomplete. Synapsins are synaptic vesicle (SV)-associated phosphoproteins that represent the major presynaptic targets of PKA. We show that, in hippocampal neurons, cAMP-dependent pathways affect SV exocytosis and(More)
We have investigated the potentiating action of cAMP on L-currents of rat chromaffin cells and the corresponding increase of Ca(2+)-evoked secretory responses with the aim of separating the action of cAMP on Ca(2+) entry through L-channels and the downstream effects of cAMP/protein kinase A (PKA) on exocytosis. In omega-toxin-treated rat chromaffin cells,(More)
The Cl- currents activated by GABA via GABAA receptors in rat cerebellum granule cells in culture were studied by whole-cell patch-clamp. These currents were measured at various extracellular pH. The currents activated by 100 microM GABA, both the peak and the steady-state component, increase at acidic pH's and decrease at basic pH's. The transition point(More)